Aptitude - Alligation or Mixture - Discussion

Simple: in question given he replace milk with water three times. Once he replaces then further repeat process two times.

40 litre milk ----> 4 litre milk removed (4 is 10% of 40) = 36 litre left.

Now again 4 litre milk removed (again 10% removed) from 36 litre mean 3.6 litre removed = 32.4 litre left.

Now again 4 litre removed = mean 10% of 32.4 is 3.24 so 3.24 litre remove and you left with 29.16 litre!

@Shobana.

Step1: 40-(10% of 40) = 36.
Step2: 36-(10% of 36) = 32.4.
Step3: 32.4-(10% of 32.4) = 29.16.

This is the simplest method. But if you want to understand the method clearly, go through my first comment.

It's simple.

First, you take out 4ltr out of 40 ltr milk then mix 4ltr replace with water again you do further 2time means 4/40=36/40= (9/10) 3*40=29.16milk.

Please explain with simple steps!

Must follow this to all this type of questions.

4 lit drawn then ratio: 4/40 => 1/10.
Rest liquid: 9/10.

Total : Rest
(10) power 3 : 9 power is 3

Ratio becomes 1000 : 729.

Now according to question 1000 : 40,
then,
1 : 0.04

Rest liquid 729=> 729 * 0.04=> 29.16.

You are right @Manoj.

Given 40L milk.

Step1: 4L milk is replaced & 4L water is added, i.e. it now contains 40L mix of 36L M & 4L W in d ratio 9:1,

So even if you take 1L of the mix it will contain (9parts M & 1 part W) & this is repeated 2mor times.

So to calculate the amount of milk present :

1st time: 40 * 9/ (9 + 1 =10).

2nd time: 40 * (9/10) * (9/10), 3rd time: 40 * (9/10) * (9/10) * (9/10) = 29.16.

A venal contains a mixture of milk and water. Milk being 49% of the solution. Two times the mixture is taken out and replaced by water. Now the mixture contains only 9%of milk. How many litres of mixture is taken out?

Find the solution of the problem.

Best Answer @Manoj Kumar.

If mixture has two types of liquids say A and B. If you remove x% of the entire mixture it is obvious that same x% is removed from both the types of liquids from their respective quantities.

In the above example whenever we remove 4 lit of solution out of 40 lit. We are removing 10% of entire solution which means we are removing 10% of milk and also 10% of water.

After Step 1: We have 36 lit of milk and 4 lit of water.

Step 2: Here we are removing 4 lit of entire solution, which means we are removing (10% of 36 = 3.6 L of milk) and (10% of 4 = 0.4 of water). So now we are left with (36 - 3.6 = 32.4L of milk) and (4 - 0.4 = 3.6 L of water). But again the mixture is added with 4 lit of water which makes (32.4L of milk + 7.6L of water) = 40 L of solution.

Step 3: Here we are again removing 4 lit of entire solution, which means we are removing (10% of 32.4 = 3.24L of milk) and (10% of 7.6 = 0.76 of water). So now we are left with (32.4 - 3.24 = 29.16L of milk) and (7.6 - 0.76 = 6.84L of water)

But again the mixture is added with 4 lit of water which makes (29.16L of milk + 10.84L of water) = 40 L of solution.

And this process goes on. Here using Percentage method is more effective rather going with ratios.